Guarantor Disclosures (Condensed Consolidating Financial Information Statement Of Cash Flows) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Condensed Financial Statements, Captions [Line Items]
Net income	$ 385,555	$ 258,966	$ 221,393
Depreciation and amortization	146,055	133,080	130,886
Deferred income taxes	(5,793)	14,114	14,153
Net changes in working capital and other	98,237	(43,864)	(83,148)
Net cash provided by operating activities	624,054	362,296	283,284
Additions to property, plant and equipment	(386,882)	(176,843)	(81,269)
Construction of assets pending sale-leaseback	(4,308)	0	0
Acquisition of business			(10,177)
Proceeds from disposition of assets	471	2,880	914
Proceeds from repayment of loan to affiliate	1,192	1,192	763
Proceeds from sale-leaseback of assets	2,304	0	0
Proceeds from sales of equity securities	47,655	0	0
Purchase of securities and other investments	(127,834)	(30,265)	0
Settlements of derivative instruments	431	251	9,494
Net cash used for investing activities	(466,971)	(202,785)	(80,275)
Intercompany financing	0	0	0
Capitalized debt issuance costs	(2,221)	(2,697)	(3,331)
Dividends paid	(285,521)	(18,265)	(16,014)
Proceeds from debt issuance	248,818	0	0
Proceeds from exercise of stock options	10,369	5,344	3,745
Repayment of debt	(250,000)	0	0
Repurchase of common stock for treasury	(10,784)	(2,518)	0
Utilization of restricted cash	96,433	54,227	197,298
Net cash (used for) provided by financing activities	(192,906)	36,091	181,698
Net (decrease) increase in cash and cash equivalents	(35,823)	195,602	384,707
Cash and cash equivalents at beginning of the year	825,901	630,299	245,592
Cash and cash equivalents at end of the year	790,078	825,901	630,299
Westlake Chemical Corporation [Member]
Condensed Financial Statements, Captions [Line Items]
Net income	385,555	258,966	221,393
Depreciation and amortization	1,514	1,683	2,154
Deferred income taxes	45	190	7,864
Net changes in working capital and other	(410,232)	(291,666)	(245,113)
Net cash provided by operating activities	(23,118)	(30,827)	(13,702)
Additions to property, plant and equipment	0	0	0
Construction of assets pending sale-leaseback	0
Acquisition of business			0
Proceeds from disposition of assets	0	0	0
Proceeds from repayment of loan to affiliate	0	0	0
Proceeds from sale-leaseback of assets	0
Proceeds from sales of equity securities	3
Purchase of securities and other investments	(124,873)	0
Settlements of derivative instruments	0	0	0
Net cash used for investing activities	(124,870)	0	0
Intercompany financing	291,455	186,898	210,360
Capitalized debt issuance costs	(2,221)	(2,697)	(3,331)
Dividends paid	(285,521)	(18,265)	(16,014)
Proceeds from debt issuance	248,818
Proceeds from exercise of stock options	10,369	5,344	3,745
Repayment of debt	(250,000)
Repurchase of common stock for treasury	(10,784)	(2,518)
Utilization of restricted cash	96,433	54,227	197,298
Net cash (used for) provided by financing activities	98,549	222,989	392,058
Net (decrease) increase in cash and cash equivalents	(49,439)	192,162	378,356
Cash and cash equivalents at beginning of the year	803,320	611,158	232,802
Cash and cash equivalents at end of the year	753,881	803,320	611,158
Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net income	412,942	294,464	246,536
Depreciation and amortization	141,388	127,807	125,002
Deferred income taxes	(5,962)	14,225	6,048
Net changes in working capital and other	94,930	(45,667)	(87,299)
Net cash provided by operating activities	643,298	390,829	290,287
Additions to property, plant and equipment	(385,919)	(175,706)	(79,928)
Construction of assets pending sale-leaseback	(4,308)
Acquisition of business			(10,177)
Proceeds from disposition of assets	449	2,877	914
Proceeds from repayment of loan to affiliate	0	0	0
Proceeds from sale-leaseback of assets	2,304
Proceeds from sales of equity securities	47,652
Purchase of securities and other investments	(2,961)	(30,265)
Settlements of derivative instruments	431	251	9,494
Net cash used for investing activities	(342,352)	(202,843)	(79,697)
Intercompany financing	(296,490)	(185,522)	(210,614)
Capitalized debt issuance costs	0	0	0
Dividends paid	0	0	0
Proceeds from debt issuance	0
Proceeds from exercise of stock options	0	0	0
Repayment of debt	0
Repurchase of common stock for treasury	0	0
Utilization of restricted cash	0	0	0
Net cash (used for) provided by financing activities	(296,490)	(185,522)	(210,614)
Net (decrease) increase in cash and cash equivalents	4,456	2,464	(24)
Cash and cash equivalents at beginning of the year	2,517	53	77
Cash and cash equivalents at end of the year	6,973	2,517	53
Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net income	(1,659)	(2,869)	1,427
Depreciation and amortization	3,153	3,590	3,730
Deferred income taxes	124	(301)	241
Net changes in working capital and other	2,256	1,874	1,301
Net cash provided by operating activities	3,874	2,294	6,699
Additions to property, plant and equipment	(963)	(1,137)	(1,341)
Construction of assets pending sale-leaseback	0
Acquisition of business			0
Proceeds from disposition of assets	22	3	0
Proceeds from repayment of loan to affiliate	1,192	1,192	763
Proceeds from sale-leaseback of assets	0
Proceeds from sales of equity securities	0
Purchase of securities and other investments	0	0
Settlements of derivative instruments	0	0	0
Net cash used for investing activities	251	58	(578)
Intercompany financing	5,035	(1,376)	254
Capitalized debt issuance costs	0	0	0
Dividends paid	0	0	0
Proceeds from debt issuance	0
Proceeds from exercise of stock options	0	0	0
Repayment of debt	0
Repurchase of common stock for treasury	0	0
Utilization of restricted cash	0	0	0
Net cash (used for) provided by financing activities	5,035	(1,376)	254
Net (decrease) increase in cash and cash equivalents	9,160	976	6,375
Cash and cash equivalents at beginning of the year	20,064	19,088	12,713
Cash and cash equivalents at end of the year	29,224	20,064	19,088
Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Net income	(411,283)	(291,595)	(247,963)
Depreciation and amortization	0	0	0
Deferred income taxes	0	0	0
Net changes in working capital and other	411,283	291,595	247,963
Net cash provided by operating activities	0	0	0
Additions to property, plant and equipment	0	0	0
Construction of assets pending sale-leaseback	0
Acquisition of business			0
Proceeds from disposition of assets	0	0	0
Proceeds from repayment of loan to affiliate	0	0	0
Proceeds from sale-leaseback of assets	0
Proceeds from sales of equity securities	0
Purchase of securities and other investments	0	0
Settlements of derivative instruments	0	0	0
Net cash used for investing activities	0	0	0
Intercompany financing			0
Capitalized debt issuance costs	0	0	0
Dividends paid	0	0	0
Proceeds from debt issuance	0
Proceeds from exercise of stock options	0	0	0
Repayment of debt	0
Repurchase of common stock for treasury	0	0
Utilization of restricted cash	0	0	0
Net cash (used for) provided by financing activities	0	0	0
Net (decrease) increase in cash and cash equivalents	0	0	0
Cash and cash equivalents at beginning of the year	0	0	0
Cash and cash equivalents at end of the year	$ 0	$ 0	$ 0